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Background The Scale for the Assessment and Rating of Ataxia (SARA) is a commonly used scale measuring the severity of cerebellar ataxia and is a candidate for outcome measurement in foreseeable clinical trials in Autosomal Recessive Spastic Ataxia of Charlevoix-Saguenay (ARSACS). Documenting its psychometric properties in this population will accelerate clinical trial readiness. The objectives of this study were to document the content and construct validity, the internal consistency, and to explore the 2-year responsiveness and the 4-year interpretability of the SARA in ARSACS. Methods The first phase of the study consisted of an international Delphi survey to document the content validity. The second phase consisted of a methodological study from the secondary analysis of a longitudinal study to document the construct validity in 69 participants. Responsiveness to change and interpretability of the SARA was explored among a sub-sample of participants (n = 32 and n = 16, respectively). Results The SARA demonstrates adequate content validity with possible influence of pyramidal and/or neuropathic involvement. It demonstrates excellent construct validity (rs = 0.77–0.95) and internal consistency (Cronbach's α = 0.89). The responsiveness to change was not significant, and the interpretation of change score increased by 1.9 ± 2.5 falling below the minimal detectable change threshold of 3.06. Conclusions The SARA has shown evidences of adequate content validity and excellent construct validity in ARSACS. Responsiveness to change and interpretability will need to be further documented among a larger sample over a longer period of time.

Background and purpose Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) diagnosis is based on the presence of three main clinical features: 1) ataxia, 2) pyramidal involvement, and 3) axonal neuropathy. This study aimed to explore, among a cohort of adults with ARSACS, the prevalence of other signs and symptoms than those commonly describe in this disease and compare their prevalence between younger ( Methods A clinical interview based on a standardized questionnaire was conducted. It included the following items: memory and concentration problems, hearing impairment, epilepsy, spasms, choreathetosis, neuropathic pain, cramps and fecal incontinence. Results A total of 43 participants were interviewed, with a mean age of 38.9 years and 51.2% were men. Spasms (55.8%), cramps (53.5%), and concentration problems (39.5%) were the most frequent manifestations. Except for choreathetosis, which was present in only one participant, all other signs and symptoms were present in 9.3% to 29.3% of participants. Conclusions People with ARSACS may experience many other clinical manifestations than the most commonly described. This study is a preliminary step toward the development of a comprehensive evidence-based clinical care guideline for this population.

Objective Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) is a neuromuscular disease leading to several impairments, including decrease of lower limb coordination. The Lower Extremity Motor Coordination Test (LEMOCOT) is an outcome measure recently developed for stroke population. The aim of this study was to document: 1) intra- and interrater reliability; 2) the standard error of measurement and minimal detectable change; and 3) the construct validity of the measurements obtained with the LEMOCOT in the adult ARSACS population. Results The LEMOCOT has shown a good intra- and interrater reliability with an intraclass correlation coefficient ranging from 0.92 to 0.97 for both dominant and non-dominant side. The construct validity (hypothesis testing) is satisfying where LEMOCOT's score negatively correlated with participants' age ( r = − 0.74) and the score of the Scale for the Assessment and Rating of Ataxia ( r = − 0.86) and positively correlated with the balance and mobility tests ( r = 0.82 with the Berg Balance Scale, r = 0.61 with the Six-Minute Walk Test, r = 0.57 with the 10-Meter Walk Test). The LEMOCOT was also able to distinguish between patients according to disease stages. Conclusion The LEMOCOT is a valid and reliable tool to assess lower limb coordination in the ARSACS population for whom the lack of coordination is a common symptom.

Background Myotonic dystrophy type 1 (DM1) is an inherited neuromuscular disease causing, among other symptoms, fatigue and excessive daytime sleepiness, which are frequently undifferentiated by patients and/or clinicians. The Fatigue and Daytime Sleepiness Scale (FDSS) has been devised to measure these two overlapping symptoms as a single clinical entity. Objective To further examine the reliability and the construct validity of the FDSS in patients with DM1. Methods The scale was administered to 48 DM1 patients on two occasions at a 2 week-interval. Intra-rater reliability and internal consistency were established by calculating the intraclass correlation coefficient (ICC) and Cronbach's alpha, respectively. Construct validity was assessed by using the known-group method. More precisely, the mean FDSS score of patients with and without subjective complaints of fatigue and/or sleepiness was compared. Results The FDSS showed good intra-rater reliability (ICC = 0.83) and acceptable internal consistency (Cronbach's alpha = 0.6). Also, the FDSS was able to distinguish between patients who had fatigue and sleepiness complaints from those who did not (mean FDSS score of 10.6 vs 8.0, p = 0.01), suggesting good construct validity. Conclusion Overall, the present study supports the continued use of the FDSS as a reliable and valid instrument to measure fatigue and daytime sleepiness in patients with DM1 for either clinical or research purposes.

Objective To assess the construct validity of the 10-Meter Walk Test (10mWT), Six-Minute Walk Test (6MWT), Berg Balance Scale (BERG), and Timed Up and Go (TUG) in adults with Autosomal Recessive Spastic Ataxia of Charlevoix-Saguenay (ARSACS), in addition to the interrater reliability of the 10mWT and 6MWT. Methods Reliability was determined using the intraclass correlation coefficient (ICC). Validity was determined first by correlating the 10mWT, 6MWT, BERG, and TUG with participant's age, lower limb coordination, and disease severity, and then by assessing their capacity to distinguish between participants based on sex and disease stages. Results Interrater reliability of the 10mWT at both comfortable and maximum speed as well as the 6MWT is excellent (ICC = 0.97–0.99). Construct validity of the four tests was confirmed, as showed by the high correlations with age, lower limb coordination, and overall disease severity (ρ = 0.64–0.97). Conclusions The four tests assessed for their metrological properties in this study showed to be valid instruments to use in the ARSACS population. The 10mWT and 6MWT are also highly reliable. BERG and TUG reliability will need to be assess in a future study.